Method of and apparatus for coating containers



R. E. .1. NoRDQuls'r ETAL 2,952,567

sept. 13, 1960 METHOD OF AND APPARATUS FOR COATING CONTAINERS Filed Feb. l0, 1958 16 Sheets-Sheet 1 INVENTORS J. /voeDqU/sr 7F fv. .BPA @E2 ,e0/VAL D E.

A 7' TOE/VEYS Sept* 13, 1950 E. J. NoRDQulsT ET AL 2,952,567

METHOD OF AND APPARATUS FOR COATING CONTAINERS Filed Feb. 10, 1958 16 Sheets-Sheet 2 HG. 3 ff 4 7' TOP/VEYS Sept 13, 1950 R. E. .1. NoRDQulsT ET AL 2,952,567

METHOD OF AND APPARATUS F OR COATING CONTAINERS Filed Feb. l0, 1958 16 Sheets-Sheet 3 INVENTORS ,90A/ALD E. .z /vaea'm/Asr TTOENE YS SePt- 13, 1950 R. E. J. NoRDQulsT ET AL 2,952,567

METHOD OF' AND APPARATUS FOR COATING CONTAINERS Filed Feb. l0, 1958 16 Sheets-Sheet 4 BY aw/Q @f/m /f TURA/5x5 Sept. 13, 1960 R. E. J. NoRDQUlsT ETAL 2,952,567

` METHOD oF AND APPARATUS FOR coA'rING CONTAINERS Filed Feb. 10, 1958 16 Sheets-Sheet 5 I l l g I l l l l l l l l l l l M l @Eri/0 12 A l BY MMA/? 242W* ZW/MMA /T TENE YS Sept. 13, 1960 R. E. J; NQRDQUIST ETA.. 2,952,567

METHOD OF' AND APPARATUS FOR C'OATING CONTAINERS 16 Sheets-Sheet 7 Filed Feb. l0, 1958 TTE/VEYS Sept 13, 1950 R. E. J. NoR'DQUlsT ET AL 2,952,567

METHOD OF AND APPARATUS FOR COATING CONTAINERS Filed Feb. 10, 1958 16 Sheets-Sheet 8 T 5 5 A Y www M ma e we W w Nwe@ r JJM A i m WV M e SBP# 13, 1950 R. E. J. NoRDQuls-r E1- AL 2,952,567

METHOD OF AND APPARATUS FOR lCOATING CONTAINERS Filed Feb. 10, 1958 FIG.8

` 16 Sheets-Sheet 9 IN V EN TORS /l Trae/VE Ys R. E. J. NORDQUIST ET AL Sept. 13, 1960 2,952,567 AND APPARATUS FOR' COATING CONTAINERS METHOD OF Filed Feb. 1o, 1958 16 Sheets-Sheet 10 Y 1N V EN TOR5 PON/M D E.

Sept 13, 1960 R. E. J. NoRDQUlsT ETAL 2,952,567

METHOD OF AND APPARATUS FOR VCOATING CONTAINERS Filed` Feb. l0, 1958 16 Sheets-Shelet 12 il! l! 2,952,567 METHOD OR ANO APPARATUS FOR OOATINO CONTAINERS Filed Feb. 10, 1958 Sept. 1,3, ,1960 R. E. J. NoRnQuls-r :TAL

16 Sheets-Sheet 15 INVENTORS PO/V E LM/.Q www.

Sept. 1 3, 1960 R. 5J. NoRDQuls'r ETAL 2,952,567

Y METHOD OF' AND APPARATUS FOR COATING CONTAINERS Filed Feb. 1o,y 195s 16 sheeis-sheet i4 F|G.2| Q .v

/Z/f Zi. ,f V /7/ u l I /17 H, k l I l 5 ,I A J ff 4f v: V l 1 f# s M e Ms H gf ZA ZA g L A l g; I 4 w www METHOD F AND APPARATUS FOR COATING CONTAINERS Ronald E. J. Nordquist, Summit, and Leif N. Brager,

Maplewood, NJ., assignors to American Can Cornpany, New York, N.Y., a corporation of New Jersey Filed Feb. 10, 1958, Ser. No. 714,235 17 Claims. (Cl. 117-95) The present invention relates to a method of and apparatus for applying a iluid liquid-proofing material such as paran or the like to the interior and exterior surfaces of empty fibre containers used for packaging milk and other liquid products and has particular reference to a novel method and apparatus for submerging the containers in the liquid-proofing material for the applying operation.

In the manufacture of libre milk containers, the application of .a film of liquid-proofing material to the interior and exterior surfaces thereof is most practically effected by immersing and passing the containers through a long trough or bath filled with the liquid-proofing material. Where speed of travel of the containers moving through the bath is immaterial, this method has proved to be satisfactory. However where high speed production is required, the application of the liquid-proofing material in this manner is impossible since the high speed movement of the containers produces considerable splashing of the liquid-proong material and creates undue stresses and strains on the containers with the result that containers are often incompletely coated and are frequently damaged beyond use.

It is an object of the instant invention to overcome this diiculty by the provision of a method of and apparatus for submerging containers individually in individual traveling baths of the liquid-proofing material so that the containers may travel at high speed through the apparatus and yet be fully coated interiorly yand eXteriorly without splashing the proofing material and `without creating strains and stresses on the containers.

'Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 is a top plan view of an apparatus embodying the instant invention and utilized for carrying out the steps of the instant method invention;

Fig. 2 is a side elevation of the apparatus shown in Fig. 1;

Fig. 3 is an enlarged sectional view taken substantially along the line 3 3 in Fig. l, with parts broken away;

Figs. 4 and 5 are enlarged transverse sectional views taken substantially along the respective lines 4 4, 5 5 in Fig. 1, with parts broken away;

Figs. 6 and 6a taken together are enlarged sectional views showing a horizontal section taken substantially along the line 6 6 in Fig. 2, with parts broken away;

Figs. 7 and 7a taken together are enlarged sectional views showing a horizontal section taken substantially along the line 7 7 in Fig. 2, with parts broken away;

Fig. 8 is a fragmentary enlarged sectional view taken substantially along the line 8 8 in Fig. 6;

Figs. 9, and ll are fragmentary top plan sectional views taken substantially along the respective lines `9 9, 10 10, 11 11 in Fig. 8;

Fig. 12 is a fragmentary enlarged elevational View as viewed substantially along the curved line 12 12 in Fig. 6;

Fig. 13 is a fragmentary enlarged elevational view as viewed along the line 13 13 in Fig. 6a;

Fig. 14 is an enlarged sectional detailed view taken substantially along the line 14- 14 in Fig. 13, with parts broken away;

Fig. 15 is a top Fig. 14;

Fig. 16 is an enlarged sectional view taken substantially along the line 16 16 in Fig. 13;

Fig. 17 is a sectional view taken substantially along the line 17 17 in Fig. 14, with parts broken away;

Fig. 18 is a fragmentary enlarged sectional view taken substantially along the curved line 18 18 in Fig. 7;

Fig. 19 is an enlarged inverted, perspective view of one of the chain elements shown in Fig. 18, the view showing a container in dot and dash lines in place in the element, parts being broken away;

Fig. 20 is an enlarged sectional view taken substantially along the line 20 20 in Fig. 18, with parts broken away;

Fig. 2l is a fragmentary enlarged sectional `view taken substantially along the line 21 21 in Fig. 7;

Fig. 22 is a fragmentary enlarged sectional view taken substantially along the line 22-22 in Fig. 7a;

Fig. 23 is an enlarged perspective view of a container adapted to be coated by the instant method and apparatus invention; and

Figs. 24 to 28 inclusive are enlarged schematic views illustrating the method steps of the invention.

As a preferred plan View of the element shown in Container, although the invention is equally well adapted to other types of containers.

Such a container A is en- 1s then poured into the enclosed con- This applying nozzle E. The paraflin as desired. If there is any tendency of loat in the bucket, it is desirable to partially fill the container before starting to iill the bucket.

When the container A is completely submerged in the paratlin, interiorly and exteriorly, it is permitted to soak for `a predetermined period to effect a desired penetration of the paraflin into the fibre material of the container. The container A is then removed from the bath of paraiiln and allowed to drain for a predetermined period to remove the excess parain. This preferably is effected by inverting the bucket D and the container therein as shown in Fig. 26 to permit the paraiiin to run out of the bucket and the container.

After its draining period, the coated container A is uprighted to its original position as shown in Fig. 27 to cause some of theparain on the interior surfaces of the container to ow down toward the container bottom to produce a reinforcing fillet F (Fig. 27) inside the container at and around the bottom corners of the container.` This is followed by a setting or hardening of the paraffin in the bottom portion of the container, both interiorly and exteriorly. For this purpose the bottom portion of the container is cooled, preferably by immersing the bottom portion of the container into a water bath .G as shown in Fig. 28.

These method steps'preferably are effected automati- Vcally in a continuously operating apparatus in which there is provided a plurality of the buckets D and in which the buckets travel through the machine so as to provide individual moving baths of the liquid-proofing material for each container. Thus each container can be readily submerged in its bath of parafn without creating on it any undue strains or stresses and while the bucket is traveling at desirable high speed rates of production.

In the apparatus portion of this invention, there is disclosed one form of machine which comprises a long housing 31 (Figs. 1 and 2) enclosing a plurality of endless chain conveyors arranged in horizontal relation, at levels one below the other. These conveyors are continuously operated. Briey, the containers A are fed into the machine in a substantially continuous procession at the entrance end of the machine (at the left as viewed in Figs.

1 and 2) and are dropped individually into the buckets D at this entrance end of the machine. The buckets D are secured in spaced relation to the uppermost conveyor, called a coating conveyor 32, which carries the thus enclosed containers the full length of the housing 31 to and around the discharge end of the machine (at the right as viewed in Figs. 1 and 2).

At the discharge end of the mcahine, the containers A and the buckets D are filled with the paraffin hereinbefore mentioned to completely submerge the containers, while the conveyor continues to move. Following this submerging operation, the conveyor 32 carries the containers along a sinuous path of travel through the housing 31. This travel provides a period for the parain to soakin, followed by an inversion of the buckets and the containers to effect draining of excess parafn from the containers and the buckets while the containers remain in the buckets. During further advancement of the conveyor 32, the buckets D and their containers A are turned into an upright position and held in this position for a predetermined period to produce the llet F. Following this, the conveyor 32 again inverts the buckets D and their containers and thus discharges the containers in their inverted position to the next lower level conveyor, a cooling conveyor 33 (Fig. 2).

The cooling conveyor 33 is located primarily at the entrance end of the-machine and a container received thereon is immediately turned into an upright position and lowered slightly to immerse its bottom end portion into a water cooling trough for setting the parain as mentioned hereinbefore. Immediately following this cooling operation, the cooled containers are dropped to the next lower level, where they are received on a transfer conveyor 34 (Fig. 2). This transfer conveyor 34 carries the containers along a sinuous path of travel terminating at the discharge end of the machine, to permit drying after the water immersion and to allow for complete setting or lhardening of the parafn on the upper portion of the containers. At the discharge end of the machine, the containers are discharged to any suitable place `of deposit.

Reference will now be had to the drawings in more detail. The uppermost level or coating conveyor 32 is actuated by a pair of spaced, horizontally disposed ring "a plurality of container sprockets 41, 42 (Figs. 4, 5, 6 and 6a) located respectively at the entrance end and the discharge end of the housing 31. These sprockets 41, 42 are secured to rotatable drums 43, 44 respectively mounted on vertical rotatable shafts 45, 46 located at the ends of the housing and journaled in top and bottom bearings in the housing as shown in Figs. 4 and 5. Shaft 45, at the entrance end of the machine is the drive shaft. This shaft 45 is rotated through a lower level drum 4S (Fig. 4) which is secured to the shaft and which carries a ring gear 49 which meshes with and is driven -by a pinion 51 of a conventional speed reduction unit 52 actuated through a sprocket and chain connection 53 with an electric motor 54 (see Figs. 1 and 2).

Intermediate the main sprockets 41, 42, the coating conveyor 32 operates over a plurality of idler sprockets 56, 57 (Fig. 6a) located adjacent the discharge end of the machine and similar idler sprockets 58, 59, 60 (Fig. 6) located adjacent the entrance end of the machine to provide the sinuous path of travel of the conveyor `as mentioned above. These idler sprockets are mounted on short vertical shafts journaled in bearing blocks 61 (Fig. 2) which extend up from a horizontal plate 62 secured in the housing 31 at a level between the coating conveyor 32 and the transfer conveyor 34 (see Figs. 2 and 5).

The coating conveyor 32 itself, comprises an endless chain of long links 64 (Figs. 13, 14, 16 and 17), connecting together, a plurality of swivel blocks 65 which are rotatable transversely of the conveyor, on pivot pins 66 formed on alternate links of the chain. These swivel blocks 65 carry the buckets D and also carry a pair of laterally extending trunnions 67, located one on each side of each block. The trunnions carry support rollers 68 which ride on a pair of spaced and parallel tracks 69 which support the conveyor 32. The tracks 69 are secured to a channel shaped support member 70 which extends entirely along the path of travel of the conveyor and which at certain points is twisted to rotate the swivel blocks 65 to invert the buckets D as mentioned above. In order to properly guide the swivel blocks 65 and the buckets D attached thereto, each block 65 carries` a depending (as viewed in Fig. 14) trunnion 72 having a guide roller 73 which operates between a pair of spaced and parallel guide tracks 74 secured to the channel mem- Vber 70.

top. These buckets D as viewed in Fig. 14, extend up in a vertical relation from the swivel blocks 65, with the openrend on top. Inside the buckets, there is provided locating ribs 76 which extend inwardly from the side walls of the buckets to properly locate the square milk containers A to be received therein, as shown in Fig. 15. On the bottom of the buckets there is provided upwardly extending ribs 77 to locate the containers A in spaced relation to the bottom of the buckets. Thus a space is provided entirely around the container for the paran mentioned above.

With such a construction of coating conveyor 32, the buckets D are spaced along the conveyor and travel with the conveyor continuously. As the conveyor 32V travels around the driving sprocket 41 at the entrance end of the machine, the buckets D are in an upright position and seated in semicylindrical pockets 79 in the outer periphery of the drum 43 as shown in Fig. 4. In this position of the buckets D, the containers A are received vfor-the coating operation.

above the path of travel of the conveyor 32 aroundits `driving sprocket 41.

, This feeding' mechanism 80 preferably comprises an inclined endless chain feed-in conveyor 82 (Fig. 3) which operates over an idler sprocket 83 mounted on a horizontal shaft 84 and over a driving sprocket 85 mounted on a horizontal shaft 86. These shafts 84, 86 are journaled in bearings 87 formed in an inverted U-shaped bracket 88 (see also Fig. 4) disposed in an opening 89 in the top of the main housing 31. The driving shaft 86 (see Fig. 4) is longer than the idler shaft 84, and at its inner end carries a bevel gear 91 which meshes with and is driven continuously by a bevel gear 92 mounted on the main vertical drive shaft 45.

The feed-in conveyor 82 carries a plurality of adjacently disposed right angle pocket members 94 (Fig. 3) which travel with the conveyor and which are arranged to pass under a vertical stack of the containers A. These containers A are disposed in a horizontal position, lying on their sides, one on top of the other, with their illing openings B facing in one direction, and the entire stack retained in a vertical magazine 95 secured to and extending through the top of the bracket 88, as best shown in Fig. 3. The magazine receives the containers from any suitable source of supply, preferably in a substantially continuous procession of contiguous containers. The :lower end of the magazine terminates adjacent the upper inclined run of the conveyor 82 so that as each pocket member 94 on the conveyor passes under the magazine,

the pocket picks off the lowermost container A in the stack and carries it down toward the coating conveyor 32. A guide rail 96 (Fig. 3) disposed adjacent the path of travel of the feed-in conveyor 82 retains the picked-olf containers in their pocket members 94.

The feed-in conveyor 82 operates in time with the rotation of the drum 43 which carries the coating conveyor driving sprocket 41 so that the containers will be delivered individually into the buckets D traveling around the drum. To effect this delivery eiiciently, the upper edge of the drum 43 carries a plurality of radially disposed horizontal V-shaped shoes 98 having curved depending extensions 99 (see Figs. 3 and 4). There is one of these shoes 98 disposed above each bucket pocket 79 in the drum 43, with the depending extension 99 of the shoe vertically aligned with the upper end of the pocket. These shoes 98, with the rotation of the drum 43, pass under the lower end of the inclined feed-in conveyor 82, in time with the advancement of the pocket member 94.

Hence as each pocket member 94 moves into register with a shoe 98, it transfers its picked-olf container A to the shoe 98, rand moves away, upwardly and empty. The transferred container A on the shoe 98 is retained in place by a series of spaced and parallel guide rails 101 (Fig. 3) which engage the container at its ends and at the uppermost corner edge of its sides as shown in Fig. 3. As shown in Fig. 6, these guide rails 101 extend halt"- way around the periphery of the drum 43 and are twisted so as to slide the container endwise along the shoe 98, outwardly and downwardly onto yand along the vertical shoe extension 99 to position the container vertically, i.e. in an upright relation directly over the top of an adjacent bucket D. At the termination of the guide rails 101, the container drops into the bucket D where it is fully enclosed thereby, except its top end, for the coating operation. A container A thus received into a bucket D is carried in this upright position, by the coating conveyor 32 toward the sprocket 42 at the discharge end of the machine.

As a bucket D with its received container A starts traveling around the sprocket 42 at the discharge end of the machine, it meshes with and is retained in upright position by one of a plurality of spaced pockets 103 (Fig. in the drum 44. There is one of these pockets 103 for each bucket D on the coating conveyor 32 and they are similar to the pockets 79 in the entrance end drum 43. Above each pocket 103, the drum 44 carries a stationary linger 104 which engages against the friction plug closure element C on the container A to hold the closure element the container Ifrom the bucket.

open.' Above each finger 104, the drum' 44 carries a normally closed nozzle 105 having a discharge oriiice of suiicient size and in proper alignment with `the open top of the bucket D so as to discharge a iiuid liquid-proong material such as paraiin wax, into the open filling opening B of the container A and also into the bucket D in the space around the container.

Each nozzle 105 is provided with a rotatable valve 107 having a star wheel 108 outside the nozzle for engagement with yand partial rotation by a pair of spaced fixed pins 109, 110 carried by the main housing 31 and in the path of travel of the star Wheels 108 as they travel with the drum 44, to open and close the valves 107 at predetermined points during this travel (see Fig. 6a).

The valves 107 communicate with the bottom of a circular closed reservoir 111 (Figs. 5 and 6a) which is secured to the drum 44 and which rotates therewith. This reservoir 111 is connected by a plurality of radially disposed pipes 112 to a hollow collar 113 formed in the hub of the drum 44 surrounding the vertical shaft 46. The upper end of the collar 113 communicates with a stationary, hollow cap 114 which rides on and is sealed against a liange 115 of the collar. The cap 114 is connected by a pipe 116 to a suitable source of supply of the paraiin coating material.

Hence as a bucket D with its enclosed container A travels around the sprocket 42 with the drum 44, `the valve 107 for this bucket is opened by the pin 109 and the nozzle 10S discharges parati-1n into the container A and -into the bucket D to completely submerge this container, interiorly and exteriorly. When the bucket reaches the pin 110, the valve 107 is closed to out off the flow of paraliin. :In this manner the coating material is applied to all interior and exterior surfaces of the container as hereinbefore mentioned.

Following this operation the bucket D and its submerged container A are carried by the coating conveyor 32 back toward the entrance end of the machine, to and around the idler sprocket 58 (Figs. 6 and 6a) and thence toward the sprocket 56 to permit the parain to soak into the container. As the bucket D approaches the idler sprocket 56, the coating conveyor track members l69, 70, 74 (Fig. 14) twist into an inverted position similar to that shown in Fig. 13, to invert. the bucket D and Iits container A to eiect discharge of the paraffin from the container and the bucket. A guide rail 121 (Fig. 6a) disposed adjacent the twisted portion of the track members retains the container in its bucket while in this inverted position. This rail 121 extends under the track members -to and around the sprockets 56 and 59 yand terminates adjacent the sprocket 57. As the bucket and its container in inverted position advance along this path of travel, the excess parain drains away from the container. The used parain falls onto the plate 62 from which it is drained in any suitable manner.

As the inverted bucket D and its drained container A approaches the idler sprocket 57 (Fig. 6a) it traverses a second twisted section of the track members `69, 70, 74 as shown in Figs. 13 and 16 and this turns the bucket and its container into an upright position. The righted bucket and container remain in this position `during their travel back toward the sprocket 60 (Fig. 6) for the purpose of permitting some of the paratiin on the interior of the container to ow down into the inside corners at the bottom of the container to produce the lillet F hereinbefore mentioned.

As the upright bucket and container approach the sprocket 60 (Fig. 6) the bucket traverses another twisted section of the track members 69, 70, 74 to invert the bucket and its container in preparation for discharge of A curved guide rail 123 (Fig. 6) p disposed adjacent this twisted section ternporarily holds the container in its bucket until the bucket is fully inverted.

` The sprocket [60 is disposed in the same horizontal plane with and substantially tangential to the coating conveyor drive sprocket 41 on the vertical drive shaft 45 (see Figs. 8 and 9), so that as a bucket D travels around the idler sprocket 60 to the point of tangency with the drive sprocket 41, vthe bucket leaves the idler sprocket 60 and travels around the drive sprocket 41. At substantially lthe same point of tangency between these sprockets, the guide rail 123 terminates and thereby permits the inverted container to drop out of its bucket D while the empty bucket starts its travel around the drive sprocket I41 to begin another cycle of operation. i The Vempty bucket D immediately rides over a twisted section 124 of the track members 69, 70, 7'4 disposed adjacent the periphery of the drive sprocket 41 as shown in Figs. 9, and l2 and this turns the bucket into an upright position for passage under the container inlet conveyor 82 as shown in Fig. 3 for the reception of another container and to begin another cycle of operation.

The container A that drops out of the bucket D, when it is inverted at the idler sprocket 60, falls vertically down into and along a vertically disposed V shaped guide pocket 126 (Figs. 8, l1 and l2) in a guide drum 127 secured to and rotating with the drive shaft 45. This drum 127 is located directly under the coating conveyor drum `43 as bestrshown in Fig. 4. There are a plurality of the guide pockets 126 spaced around the outer periphery ofthe drum 127.

The drum 127 carries a sprocket 128 which drives the cooling conveyor 33 (Fig. 7). The cooling conveyor 33 surrounds substantially three quarters of the sprocket 128 and thence operates over anidler sprocket 131 (Fig. 7) and returns to an idler sprocket 132 disposed immediately adjacent the drum sprocket 128 and carried on the same vertical shaft on which the sprocket 60 is mounted but at a lower level (see Fig. 8).

The cooling conveyor 33 is similar in construction to the coating conveyor 32 and comprises a series of link connected swivel blocks 135 (Figs. 18, 19, and 20) each having laterally extending trunnions carrying support rollers 136 which ride on support tracks 137 on a channel shaped track member `138, and a depending trunnion which carries a guide roller 139 which operates in guide tracks 141 -in the track member 138. Each of the swivel blocks 135 carry a pair of upright spaced and parallel prongs 143 which together constitute a container holder and which are formed with inwardly opposed vertical grooves 144 for receiving and holding a container A between them as shown in Figs. 19 and 20. The upper ends of the prongs 143 preferably are formed with outwardly flared lips 145 to facilitate entrance of the container into the grooves.

There are a plurality of the container holding devices 143 arranged in spaced relation along the cooling conveyor 33 in the same manner and spacing of the buckets D on the coating conveyor 32. These holding devices 143 lalign with the guide pockets 126 on the drum 127 as the conveyor starts its travel around the sprocket 128 at the idler sprocket 132 (Figs. 7 and 8). Hence when a container A drops from its bucket D into an aligned guide pocket 126 as mentioned above, it is guided by this pocket into place in the valigned container holder 143, as best shown in Fig. 8. The container thus received in a holder 143 is in an inverted position.

Immediately following the reception of a container in a holding device 143, its swivel block 135 of the cooling conveyor 33, while the latter advances around the sprocket 128, traverses a twisted section 147 (Figs. 7, 11 and 12) of the cooling conveyor track members 137, 138, 141 and thus turns the holding device 143 and its container A, outwardly and downwardly as shown in Fig. 12 to position the container A into an upright position with its lling opening B at the top of the container. -A

8 curved guide rail'148 guides the container along its bottoni end during this uprighting operation.

In this upright position, the container A still retained by its holding device V143 travels around the drum sprocket 128 for substantially 180 degrees of travel as best shown in Fig. 7. During this travel, the guide rail 148 on which the container rests, dips down into a cool-ant or water bath 151 (Figs. 7 and 18) contained in a circular reservoir or trough 152 carried by and rotating with the lowermost level drum 48 (see Fig. 4). The container A, riding over this depressed portion Vof the guide rail 148, is thus lowered into the water bath 151 so that its lower or bottom end portion is immersed in the bath. It is this cooling bath that sets or hardens the parain on'the bottom of the container, including the llet F.

The cooling water 151 is circulated through the trough 152 by Way of pipes 154 (Fig. 4) which lead from the trough 152 to a hollow collar 155 which surrounds the driving shaft 45 and rotates therewith. This collar 155 is rotatably sealed against a stationary cap 156 having a supply pipe 157 which leads to any suitable source of cooled water.

Upon completion of its substantially degree travel around the drum sprocket 128, a container A is pushed up out of the water bath 151 by an upward bend in the guide rail 148 and in this elevated position still supported by the guide rail 148 and itsA holding device 143, leaves the drum sprocket 128 and travels along a straight line path of travel toward the idler sprocket 131 as shown in Fig. 7. Along a portion of this straight line travel, the cooling conveyor 33 overlaps and runs in vertical parallel alignment with a portion of the transfer conveyor 34 mentioned hereinbefore as being disposed at the lowermost level (see Figs. 7 and 2l).

At this overlapping portion of the two conveyors 33, 34, the container supporting guide rail 148 is bent downwardly toward and terminates adjacent the path of travel of the transfer conveyor 34. As a container A advances along this portion of the guide rail 148 it gradually moves down out of its holding device 143 of the cooling conveyor 33 and at the termination of the rail 148, the container drops into a holding device 161 which is carried by the transfer conveyor 34 and which aligns vertically with the holding device 143 of the cooling conveyor as the two conveyors advance along the parallel portion of their paths of travel in timed relation.

The transfer conveyor 34 is identical in construction with the cooling conveyor 33 and like the cooling conveyor is provided with supporting and guide roller carrying swivel blocks 162 (Fig. 2l) which ride on tracks secured in a channel shaped track member -163 disposed adjacent the entire path of travel of the conveyor. 'I'he container holding devices 161 are identical with the prong construction of the holding devices 143 of the cooling conveyor 33.

After transfer of a container A to the transfer conveyor 34, the empty holding device 143 of the cooling conveyor 33 travels around the cooling conveyor idler sprocket 131 (Fig. 7) and returns to the idler sprocket 132 along a twisted section 16S of the cooling conveyor track members 137, 138, 141 which turn the empty holding device 143 into an upright position for travel around the idler sprocket 132 to receive another container A as shown in Fig. 8 for a repeat cooling cycle of operation.

Meanwhile, the container A transferred to a holding device 161 on the transfer conveyor 34 is carried along a sinuous path of travel which includes advancement to and around an idler sprocket 166 (Fig. 7a), to and around a second idler sprocket 167 and thence to and partially around a third idler sprocket 168 located at the discharge end of the machine. Beyond this third sprocket 168 the transfer conveyor 34 travels back over a fourth idler sprocket 169 (Fig. 7) and then returns by way of 

1. A METHOD OF APPLYING A FILM OF FLUID-PROOFING MATERIAL TO THE INTERIOR AND EXTERIOR SURFACES OF AN EMPTY CONTAINER HAVING A DISPENSING OPENING THEREIN, COMPRISING THE STEPS OF INSERTING THE CONTAINER IN A BUCKET WITH SAID DISPENSING OPENINGS UPPERMOST, FILLING THE CONTAINER AND THE BUCKET WITH THE LIQUID-PROOFING MATERIAL SO AS TO COMPLETELY SUBMERGE THE CONTAINER TO INSURE APPLICATION OF SAID LIQUID-PROOFING MATERIAL TO ALL EXTERIOR AND INTERIOR SURFACES OF THE CONTAINER, AND INVERTING SAID BUCKET TO DRAIN THE EXCESS LIQUID-PROOFING MATERIAL FROM THE CONTAINER TO LEAVE A FILM OF SAID MATERIAL ON THE SURFACES OF SAID CONTAINER. 